In wireless networks, data packets are lost due to channel interference and fading rather than network congestion. Thus, TCP designed for wired networks, cannot achieve a satisfying performance in wireless networks. U...In wireless networks, data packets are lost due to channel interference and fading rather than network congestion. Thus, TCP designed for wired networks, cannot achieve a satisfying performance in wireless networks. Utilizing a cross-layer mechanism to identify the course of packet loss, we have proved that a mobile-host-centric transport protocol (MCP) can achieve higher throughput than TCP Reno and New Reno in static wireless environment. In this paper, we extend the cross-layer feedback mechanism and con...展开更多
In multi-hop cognitive radio networks （ CRNs）, the heterogeneous environment increases the complexity of common control channel （CCC） formation and routing protocol design. In this paper, we consider the on-demand...In multi-hop cognitive radio networks （ CRNs）, the heterogeneous environment increases the complexity of common control channel （CCC） formation and routing protocol design. In this paper, we consider the on-demand routing protocol transmits over CCC. However, since CR transceivers （secondary users） have different available channel sets and it must vacate the licensed channel when a primary user arrives, forming a CCC becomes a main challenge in routing protocol design for CRNs. Our proposed CCC formation algorithm is based on a spectrum-tree structure, which consists of all cluster heads in CRNs. The cluster heads are with smaller moving range and lower mobility, and also act as a router in the whole network which maintains information of its cluster. Hence, a route is constituted in part by a set of cluster-head identity （ID） numbers, which represent the spe- cific cluster heads the path traverses, and in part by a set of member nodes ID numbers, which are included in the clusters containing the source and destination nodes. Due to high mobility and dynamic available spectrum, we define the stability parameters of path as two parts. One stability parameter is mobility factor, which represents the probability that a pairwise node can keep in communication range for the next flow transmission. The another stability parameter is spectrum opportunistic （SOP） factor, which represents the probability that a pairwise links can obtain the assigned spectrum band for the next flow transmission. Simulation results show that CCC formation algorithm produces a high probability of CCC formation, and the proposed routing protocol performs better than typical routing protocols.展开更多
基金Supported by the National High Technology Research and Development Program of China ( "863" Program, No. 2007AA01Z220)National Natural Science Foundation of China (No. 90604013 and No. 60702038)
文摘In wireless networks, data packets are lost due to channel interference and fading rather than network congestion. Thus, TCP designed for wired networks, cannot achieve a satisfying performance in wireless networks. Utilizing a cross-layer mechanism to identify the course of packet loss, we have proved that a mobile-host-centric transport protocol (MCP) can achieve higher throughput than TCP Reno and New Reno in static wireless environment. In this paper, we extend the cross-layer feedback mechanism and con...
文摘In multi-hop cognitive radio networks （ CRNs）, the heterogeneous environment increases the complexity of common control channel （CCC） formation and routing protocol design. In this paper, we consider the on-demand routing protocol transmits over CCC. However, since CR transceivers （secondary users） have different available channel sets and it must vacate the licensed channel when a primary user arrives, forming a CCC becomes a main challenge in routing protocol design for CRNs. Our proposed CCC formation algorithm is based on a spectrum-tree structure, which consists of all cluster heads in CRNs. The cluster heads are with smaller moving range and lower mobility, and also act as a router in the whole network which maintains information of its cluster. Hence, a route is constituted in part by a set of cluster-head identity （ID） numbers, which represent the spe- cific cluster heads the path traverses, and in part by a set of member nodes ID numbers, which are included in the clusters containing the source and destination nodes. Due to high mobility and dynamic available spectrum, we define the stability parameters of path as two parts. One stability parameter is mobility factor, which represents the probability that a pairwise node can keep in communication range for the next flow transmission. The another stability parameter is spectrum opportunistic （SOP） factor, which represents the probability that a pairwise links can obtain the assigned spectrum band for the next flow transmission. Simulation results show that CCC formation algorithm produces a high probability of CCC formation, and the proposed routing protocol performs better than typical routing protocols.
